A standard mattress assembly includes one or more layers of padding disposed on an innerspring core. Typically, the innerspring core includes a plurality of coil springs that are closely packed together in an array having a generally rectangular shape in plan with the ends of the springs lying in a common plane. The coil springs have longitudinal axes oriented parallel to one another. Conventionally, each spring is manufactured from a single, solid, coiled steel wire.
During its lifetime, mattresses, and particularly the innerspring core, endures significant stresses from daily use. Such repetitive daily use causes the coil springs in these innerspring cores to undergo many cycles of compression and release. Consequently, physical characteristics of these springs, such as coil length and pitch, begin to change over time. Moreover, the springs lose some tensile strength and become generally weaker.
To increase the durability and comfort of these mattresses, manufacturers include one or more additional layers of support and padding above and below the innerspring core. These additional layers help maintain the integrity of the innerspring core by redistributing some of the forces and stresses away from the coil springs. However, the additional layers add extra bulk and weight to the mattress assembly.
Other manufacturers have experimented with different shapes and arrangements of these coil springs, and have also attempted to add one or more strands to the coil springs to strengthen the innerspring core. However, these techniques are not as effective in redistributing the stresses and inevitably require additional layers of padding.
Accordingly, there is a need for a cushioning article configured with a stronger and more durable innerspring core while keeping the weight and size to a minimum.